This invention relates generally to a positive cam locking device for telescoping extension poles such as those used to extend the reach of painting implements. While such locking devices have been known in the art, such devices have been less then completely satisfactory in that such locking devices may cause misalignment of the poles or slippage if such locking devices are contaminated with paint or other lubricating substances. One such device is illustrated in U.S. Pat. No. 2,432,059 which uses a single eccentrically mounted cam for locking a pair of telescoping tubes.